Okay, that is a pretty neat use of illusion magic. Pity it's not shapeshifting, mind - among other things she's liable to boop her nose with the mirror because she can't see the end of her muzzle anymore.
Reminds me, I don't think Jakob ever became a cat...
[EDIT: Fixed pronouns. ]
Mariam's friends before she came to DHS were both cats. I wonder if she ever felt like she stood out haha.
I always think of illusions as adding things to what's already there but never could wrap my head around making body parts disappear or appear shorter, like Mariam's muzzle in this case. If she can balance things on her nose, it'd just look like its floating in front of her face.